The FAA released an audio recording from the Feb. 24 incident, which details the pilots talking with air traffic controllers, baffled about the object. The sighting happened around 3:30 p.m. local time over the Sonoran Desert near Phoneix, according to TheDrive.Com’s War Zone.

“Was anybody above us that passed us like 30 seconds ago?” the first pilot, who was flying a Learjet, asked.

“Negative,” an FAA air traffic controller in Albuquerque responded.

“OK,” the Learjet pilot responded. “Something did.”

“It’s a UFO!” someone responded.

“Yeah,” the pilot said while laughing.

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The FAA then asked another nearby pilot flying an American Airlines Airbus to keep an eye out for anything “passing over.” The confused pilot agreed and within a few minutes reported a mysterious object flying over the plane.

“Yeah, something just passed over us,” the American Airlines pilot said. “I don’t know what it was, it wasn’t an airplane but it passed us going the opposite direction … it was at least two to three thousand feet above us. I couldn’t make it out, whether it was a balloon or what, but it had a big reflection on it and it was several thousand feet above us, going the opposite direction.”

Someone later asked the American Airlines pilot if it was a Google balloon.

“Doubtful,” the pilot said. Someone then quickly replied, “UFO.”

In a statement to KOB 4, the NBC station in Albuquerque, the FAA essentially said it doesn’t know what the object was.

“We don’t have any comment beyond what you hear. Other than the brief conversation between two aircraft, the controller was unable to verify that any other aircraft was in the area,” the statement read.

“We have a close working relationship with a number of other agencies and safely handle military aircraft and civilian aircraft of all types in that area every day, including high-altitude weather balloons.”

The New York Times reported that the program, tasked with investigating sightings of unidentified flying objects, ran from 2007 to 2012 with $22 million in annual funding secretly tucked away in U.S. Defense Department budgets worth hundreds of billions of dollars.